POSITIVE ELECTRODE MATERIAL FOR LITHIUM SECONDARY BATTERY AND ITS MANUFACTURE

摘要

PROBLEM TO BE SOLVED: To keep a high charge rate and to provide a good charge cycle characteristic by imparting the micro-step structure of the crystal surface comprising two kinds of surfaces forming a certain angle in a positive electrode material having a specific composition structure. SOLUTION: This material for a lithium secondary battery is expressed by a chemical formula Li1+xMn2-nO4, and its crystalline surface has a micro-step structure comprising two kinds of surfaces forming an angle of 150 deg. or 210 deg.. Where x is 0<=x<=0.20. The Li1+xMn2-nO4 can be prepared by first primarily baking a precursor wherein a manganese salt and a lithium salt are mixed at 650-900 deg.C in a low-oxygen atmosphere containing 10% or less of oxygen or an inert atmosphere and by then changing the atmosphere into an oxidizing one containing 18% or more of oxygen in a cooling process of its secondary baking. Thereby, an active material having a shape where 110} and 100} planes are deposited on the crystal surface of Li1+xMn2-nO4 having a 111} crystal habit in a micro-step form is provided.